Snowblowers are designed to lift snow off the ground surface and blow the snow away from the area being cleared. Single stage snowblowers may include a scraper to lift or scrape snow from the surface, and an impeller that moves the snow up and out through a discharge chute. Two stage snowblowers include a metal auger that rotates on a horizontal axis to break up and draw snow into the housing where the impeller then forces it up and out the discharge chute.
Snowblowers may be walk behind or mounted to the front of a small tractor or utility vehicle using a hitch. A hydraulic cylinder controlled by the operator may be used to raise and lower the hitch, and another to change the angle of the discharge chute. A power take off shaft (PTO) may be connected to the snowblower to rotate the auger and/or impeller.
Snowblowers may be provided with skid shoes mounted adjacent the lower edge of each side wall of the auger housing. The skid shoes may have a bottom surface that allows them to slide over the ground surface, keeping the bottom edge of the auger housing and scraper a short distance above the ground surface, and preferably at least about ½ inch above the ground surface. Skid shoes may help prevent or minimize damage to the housing or other components of the snowblower, and to avoid bringing material other than snow into the snowblower. For example, snowblowers may encounter various different ground surfaces having different surface conditions other than cement, such as gravel, dirt, or grass. It would be desirable to raise or lower a snowblower when encountering different surface conditions, to prevent damage to snowblower components and to prevent material other than snow from entering the housing and blowing out the discharge chute.
Conventional snowblowers do not provide an acceptable solution to this problem. It is inconvenient and difficult to adjust the height of skid shoes by loosening and changing the position of several bolts or attachment mechanisms holding each shoe or skid to the housing. This is a problem when the skid shoes are covered with snow and ice. Examples of these skid shoe mechanisms are shown in U.S. Pat. Nos. 2,768,453 and 4,441,266. Conventional snowblowers also may be raised or lowered using the hydraulic lift cylinder. However, adjusting the snowblower using a lift cylinder may sacrifice good and uniform performance because the lift cylinder raises the back of the snowblower and changes the angle of approach. Some conventional snowblowers also have proposed replacing the skid shoes with rollers or caster wheels. However, rollers or caster wheels may be useful on dry or bare surfaces, but do not work as well on snow and ice. Additionally, the height of rollers or caster wheels cannot be adjusted in winter conditions without facing the same problems as skid shoes. Examples of rollers or caster wheels are shown in U.S. Pat. Nos. 3,721,025, 6,508,018 and 8,191,289. Finally, a mechanism with a pair of turning handles was proposed in U.S. Pat. No. 3,490,057. However, each handle is connected to the spindle of a disk, the spindles are threaded to casings connected to the housing, and both handles must be turned the same to keep the machine level.
A snowblower skid shoe height adjustment mechanism is needed that can simultaneously raise or lower a pair of skid shoes in winter conditions while the operator remains in the operator station.